Fixed some imgui scissor edge cases

examples/imgui_impl_vulkan_with_textures.cpp

@@ -432,8 +432,9 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
                     VkRect2D scissor;
                     scissor.offset.x = (int32_t)(clip_rect.x);
                     scissor.offset.y = (int32_t)(clip_rect.y);
-                    scissor.extent.width = (uint32_t)(clip_rect.z - clip_rect.x);
+                    // NOTE(Yan): sometimes x > z which is invalid, hence the abs
-                    scissor.extent.height = (uint32_t)(clip_rect.w - clip_rect.y);
+                    scissor.extent.width = (uint32_t)(glm::abs(clip_rect.z - clip_rect.x));
+                    scissor.extent.height = (uint32_t)(glm::abs(clip_rect.w - clip_rect.y));
                     vkCmdSetScissor(command_buffer, 0, 1, &scissor);
 
                     // Bind descriptorset with font or user texture

imgui_draw.cpp

@@ -437,7 +437,12 @@ void ImDrawList::AddDrawCmd()
     draw_cmd.VtxOffset = _CmdHeader.VtxOffset;
     draw_cmd.IdxOffset = IdxBuffer.Size;
 
-    IM_ASSERT(draw_cmd.ClipRect.x <= draw_cmd.ClipRect.z && draw_cmd.ClipRect.y <= draw_cmd.ClipRect.w);
+    // NOTE(Yan): Not sure why this happens but sometimes x > z which causes a crash in vkCmdSetScissor later on
+    // IM_ASSERT(draw_cmd.ClipRect.x <= draw_cmd.ClipRect.z && draw_cmd.ClipRect.y <= draw_cmd.ClipRect.w);
+    if (draw_cmd.ClipRect.x > draw_cmd.ClipRect.z)
+        draw_cmd.ClipRect.z = draw_cmd.ClipRect.x + 1;
+    if (draw_cmd.ClipRect.y > draw_cmd.ClipRect.y)
+        draw_cmd.ClipRect.w = draw_cmd.ClipRect.w + 1;
     CmdBuffer.push_back(draw_cmd);
 }